This section is intended to introduce various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion should be helpful in providing background information to facilitate a better understanding of the various aspects of the present invention. These statements are to be read in this light, and not as admissions of prior art.
An engine for aircraft propulsion requires intake air that is free from contaminants to provide for efficient combustion and avoid damage to internal engine components. Some known compressors and turbines are designed with small clearances between moving parts that maximize efficiency, but which also increase vulnerability to damage of engine parts from small foreign particles. Contamination of intake air, even in a small amount, may cause premature wear on engine components, increases maintenance costs, and degrades operational performance and reliability. Aircraft are exposed to contaminants when operating at low altitudes where air is frequently contaminated with material from the ground, such as sand and dust. This problem may be worse for helicopters and for tiltrotor aircraft due to rotor downwash and prolonged low-altitude operation. This problem may also be worse for fixed wing aircraft operating from unimproved airfields. Aircraft, including tiltrotor aircraft, also have a higher operating altitude than conventional helicopters and are thereby more frequently exposed to icing conditions in flight. Such conditions can cause ice to form in and around the engine intake, and this ice may damage the engine if allowed to enter the engine. A better system for preventing ice and contaminants from entering the engine is needed.